CVE-2021-30761VulnerabilityPublished 11/03/2021Updated 10/24/2026

CVE-2021-30761: Apple iOS WebKit Memory Corruption Vulnerability

Affects Apple iOSSource CISA KEV

Severity

High

No CVSS score published yet

Exploitation: Actively exploited – in CISA KEV since 11/03/2021
KEV deadline: 11/17/2021
EPSS: 10.5% chance of exploitation in 30 days – higher than 95% of CVEs

What to do

CISA required action

Apply updates per vendor instructions.

nvd.nist.gov/vuln/detail/CVE-2021-30761 (opens in a new tab)

Description

CVE-2021-30761 is a memory corruption vulnerability in Apple iOS WebKit that can lead to code execution when processing maliciously crafted web content. This affects HTML parsers using WebKit, including Apple Safari and other products relying on WebKit. The vulnerability has been exploited in the wild.

Summary

Apple iOS WebKit contains a memory corruption flaw (CWE-787) that allows remote attackers to execute arbitrary code by delivering maliciously crafted web content. This vulnerability impacts HTML parsers that utilize WebKit, including Apple Safari and potentially non-Apple products that depend on WebKit for HTML processing. Exploitation has been observed in the wild, indicating active threat usage.

Impact

Successful exploitation can result in arbitrary code execution on affected devices, potentially allowing attackers to take control of the device or execute malicious actions within the context of the WebKit process.

Mitigation

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Users and administrators should monitor Apple security updates and apply any official fixes promptly once available.

Weaknesses

CWE-787Out-of-bounds Write (opens in a new tab)

What to do

Description

AnalysisAI-generated, updated 10/24/2026, 09:40:47 UTC

Weaknesses

References

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